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Luo, W.

Publications and source records attributed to Luo, W..

At least 55 records · Page 3Linked to original sources

A colorimetric method for detecting virulent bacteriophage to Vibrio cholerae in fecal and environmental samples

BackgroundV. cholerae are often infected with vibriophages and these phages may be found associated with V. cholerae bacteria or may be detected independently from the bacteria, especially in environmental water samples. When detected, vibriophages serve as a surrogate for detection of V. cholerae and they also have an important role in the ecology of V. cholerae. Vibriophages can be detected using plaque assays or PCR, but these methods are time-consuming and require specialized laboratory resources. MethodologyTo address limitations of other methods, we developed a simple, rapid, and inexpensive colorimetric assay to detect vibriophage that can be scaled up to quickly and easily to screen a large number of samples. The assay uses resazurin and a bacterium, AC6169 that is susceptible to vibriophages ICP1, 2, and 3. Resazurin is a dye that turns color from blue to pink when added to a culture broth with growing bacteria. When a bacteria-free test sample, such as a Millipore filtered wastewater sample containing vibriophages, is added to a culture broth with AC6169, the bacteria will be lysed by the phages and will not grow, and the color of the broth will remain blue. However, if there are no phages in the sample, the bacteria will grow rapidly, and the culture broth will turn pink. We developed the assay using ICP1 spiked samples of environmental water, stool and frozen bile peptone and found it to be sensitive with a limit of detection of 4 to 40 plaque forming units/ml. ConclusionThis colorimetric assay promises to provide a convenient method to detect vibriophages on a larger scale than was possible earlier to better understand their role as a surrogate for detecting V. cholerae and to better understand their role in the pathogenesis, ecology, and epidemiology of cholera. Author SummaryWe developed a simple and inexpensive colorimetric assay to detect virulent vibriophage in samples of wastewater and stool. The assay uses resazurin, a blue dye and a unique bacterium, AC6169, that is known to be susceptible to vibriophages. Bacteria-free samples (e.g. Millipore filtrates) suspected of having vibriophage are incubated for 2 or 3 hours in a broth with AC6169, following which resazurin is added. After a further 30-minute incubation, the color of the broth is observed. If the sample contains vibriophage, the broth will remain blue, but if there are no vibriophage, the broth will turn pink. The change in color from blue to pink is due to the metabolic reaction from the growing bacteria. When vibriophage are present, they lyse the bacterium AC6169, thus preventing the color change, but if vibriophage are not present, the bacteria multiply rapidly, and the metabolic reaction causes the broth to change color to pink. Because the assay procedure is inexpensive and simple, laboratories in cholera endemic areas should find it convenient for their epidemiologic and clinical surveillance activities.

microbiology↗

CAR T cell cytotoxic responses are rapidly generated and sensitive to the unligated TCR

Chimeric antigen receptor (CAR) T cells expressing tumor-targeting engineered receptors can robustly eliminate cancer cells through secretion of cytotoxic factors. Durable remission in leukemia and lymphoma treatment has not been matched in solid tumors. Efforts to maximize tumor destruction and minimize toxicities have driven efforts to tune CAR signaling. However, the molecular mechanisms for CAR triggering and thresholds for activation are incompletely understood. Here, we measured the collection of CAR binding interactions that culminate in polarized delivery of lytic granules to the junction with the target. CAR T cells binarized cytotoxic activities in response to a few binding events and population outcomes were dominated by a subset of cells. Activation at the single molecule level matches the sensitivity of the native T cell receptor (TCR) and points to potent downstream signal propagation. Disruption of the unligated TCR with a transmembrane-targeting inhibitory peptide strongly dampened CAR T cell activation, indicating a critical crosstalk between the two receptors. Harnessing CAR T cell efficacy and reduction of toxicity will require new approaches to modify integration of the binding events, collected stochastically, that are rapidly digitized. These sensitive CAR T cell responses provide new insights into driving cytotoxic signaling through surface interaction engineering.

immunology↗

In vivo and in silico alpha-synuclein propagation dynamics: The role of genotype, epicentre, and connectivity

Neurodegeneration observed in synucleinopathies, like Parkinsons disease (PD), are hypothesized to be a consequence of the progressive accumulation and spread of misfolded alpha-synuclein (aSyn) throughout the brain. Here, we study the generalizability of this hypothesis across multiple biologically-relevant factors including genotype, aSyn species, and regional vulnerability (i.e.: does the introduction of aSyn into different brain regions have a similar impact) using a detailed longitudinal brain (using magnetic resonance imaging; [MRI]) and behavioural approaches. We first examined wild-type and M83 A53T hemizygous transgenic (engineered to over-express human aSyn) C57BL/6 x C3H mice receiving striatal inoculation with human or mouse preformed fibrils (PFFs) (n=89 mice at the last time point; n=687 MRI). Longitudinal analyses demonstrated a time-dependent increase in network-like atrophy and motor deficits, generalized across genotype and PFF species. We further derived latent dimensions relating brain-behaviour relationships revealing a pattern of sex- and genotype-relevant atrophy. Overall, atrophy was most prominent in M83 mice with mouse PFFs, while human PFFs or wild-type hosts showed attenuated effects. Changing the inoculation site to the hippocampus, a major connectivity hub, revealed differential regional vulnerability in the form of localized atrophy. Computational models previously validated in clinical PD further indicated regional vulnerability with increased predictive ability for atrophy patterns associated with striatal compared to hippocampal inoculation. Our findings reveal atrophy resulting from aSyn spreading is generalizable across genotype and PFF species, but not disease epicentres, emphasizing the role of regional vulnerability in disease progression.

neuroscience↗

piR-bmo-796514 Facilitates the Proliferation of Exogenous DNA Virus (Baculovirus) by Targeting the Host E3 Ubiquitin Ligase RNF181

PIWI-interacting RNAs (piRNAs), a class of 23-31 nucleotide non-coding RNAs, are known for silencing transposons and endogenous retroviruses that reside in animal genomes. However, the mechanisms by which host piRNAs affect exogenous viral infections, particularly those by DNA viruses, remain poorly understood. Here, we demonstrate that infection by Bombyx mori nucleopolyhedrovirus (BmNPV), a large DNA virus, induces significant upregulation of silkworm host piR-bmo-796514, which facilitates viral proliferation by suppressing the expression of E3 ubiquitin ligase RNF181. We further reveal that RNF181 exerts antiviral activity through ubiquitin-mediated degradation of Integrin 2b-like, a cellular membrane protein that interacts with viral GP64 protein to mediate BmNPV entry. This study unveils a previously unrecognized regulatory axis connecting host derived piRNAs with exogenous DNA virus infection, providing further mechanistic insights into the modulation of exogenous viral pathogenesis through the reprogramming of the piRNA pathway. Our findings not only advance the understanding of the immune escape mechanism of exogenous viruses but also provide new insights for the development of oligonucleotide antiviral drugs that target proviral piRNAs.

immunology↗

DeepPGDB: A Novel Paradigm for AI-Guided Interactive Plant Genomic Database

DeepPGDB (https://www.deeppgdb.chat) is the first AI-driven plant genomics database designed to lower technical barriers in multi-omics research by enabling natural language-based data access and analysis. Integrating over 50 high-quality plant genomes, DeepPGDB combines fine-tuned large language models (LLMs) with prompt engineering to interpret user queries, generate standardized bioinformatics commands, and retrieve or visualize genomic data. Key functionalities include sequence retrieval, BLAST alignment, gene localization, expression profiling, and population genetics analysis, all presented via an intuitive conversational interface. A summarization module further enhances biological reasoning, inferring insights such as haplotype differentiation or protein properties. Benchmarking revealed that Deepseek-r1:14b optimized for short pre-prompts delivers high accuracy and speed. By bridging computational and biological expertise, DeepPGDB democratizes genomic research, fostering interdisciplinary collaboration and accelerating discoveries in agriculture and biotechnology.

bioinformatics↗

α-Synuclein purification significantly impacts seed amplification assay performance and consistency

-Synuclein seed amplification assays are a promising diagnostic tool for synucleinopathies such as Parkinsons disease and multiple system atrophy. Standardized conditions are required to ensure a high degree of inter- and intra-laboratory reproducibility when performing these assays. A significant issue that hinders the utility of seed amplification assays is the de novo aggregation propensity of the -synuclein substrate as well as inter-batch heterogeneity. While much work has focused on determining appropriate seed amplification assay buffer compositions as well as the type and amount of seed used, a robust comparison of -synuclein substrate purification methods has not been reported. We therefore compared the utility of recombinant -synuclein purified using four different methods as seed amplification assay substrates across two laboratories. Osmotic shock-purified -synuclein monomer substrate showed the lowest propensity for de novo aggregation, which translated into being the best substrate for seed amplification assay reactions seeded with -synuclein preformed fibrils or patient brain homogenates. Furthermore, osmotic shock -synuclein monomer showed the best inter-batch reproducibility compared to all other substrates tested. As -synuclein seed amplification assays continue to evolve and move towards adoption in the clinical realm, this work showcases the vital importance of standardizing the production and characterization of recombinant -synuclein substrate. We encourage the widespread adoption of osmotic shock -synuclein monomer as the universal substrate for seed amplification assays to maximize intra- and inter-laboratory reproducibility.

biochemistry↗

Neural signature underlying the effect of intranasal vasopressin on emotional responses to spontaneous social comparison

Vasopressin, a key molecular regulator of social behavior, is implicated in promoting self-protective responses to threats against physical safety and resources. However, its role in defending against self-view threats--common in social interactions and critical to well-being--remains unclear. This study investigates the neural mechanisms through which vasopressin modulates self-protective responses to spontaneous social comparison. In a double-blind, placebo-controlled neuroimaging experiment, participants rated their satisfaction with social evaluations and monetary outcomes assigned to a stranger, friend, or themselves. Compared to placebo, vasopressin selectively intensified contrastive emotional responses to social evaluations of the stranger, decreasing satisfaction with positive evaluations and increasing satisfaction with negative evaluations, relative to those of the self or friend. At the neural level, vasopressin reduced the distinctions between the stranger and the self/friend in the medial prefrontal cortex activity, multivariate response patterns, and functional connectivity with the temporoparietal junction and precuneus, with this effect being especially pronounced among socially dominant individuals. These converging neuroimaging findings support the hypothesis that vasopressin alters the neural representation of the stranger, shifting it from a socially irrelevant figure under placebo to a psychologically salient competitor, thereby triggering self-protective emotional processes. These findings elucidate novel neuropsychological mechanisms through which vasopressin amplifies emotional defense against social threats and offer insights into potential clinical applications for psychiatric conditions characterized by impaired self-protection.

neuroscience↗

Cytokine-driven cellular polarization in preeclampsia revealed through the "Dictionary of immune responses"

BackgroundPreeclampsia (PE) is a pregnancy-related hypertensive disorder and a leading cause of maternal and perinatal mortality. Current treatments focus primarily on symptom management, as delivery remains the only definitive cure. This underscores the urgent need for innovative therapeutic strategies. Cytokines released by placental immune cells may contribute to the progression of PE and represent promising therapeutic targets. MethodsWe conducted single-cell sequencing on placental tissues obtained via cesarean section from patients with severe PE and cases of non-infectious preterm birth. Machine learning was applied to identify critical immune cells. Immune Response Enrichment Analysis was performed on these key cells to evaluate their polarization states and cytokine responses associated with PE. Additionally, we investigated cell-cell communications, key genes, and their related functions ResultsWe identified cell type-specific alterations in PE, including an increased proportion of CD4+ T cells polarized towards an IL-1- and IL-1{beta} enriched T4-c state. Altered SPP1 signaling between macrophages and CD4+ T cells was observed, indicating immune response dysregulation. Additionally, machine learning algorithms identified four hub genes, and six small-molecule drugs were predicted to hold therapeutic potential for PE. ConclusionsThis study emphasizes the importance of further understanding CD4+ T cell dynamics in preeclampsia, providing potential insights into the principles of placental immunity and contributing to the exploration of immunotherapeutic strategies

bioinformatics↗

Gut Microbiome Signatures Reflect Within-Host Subtype Diversity of Blastocystis in Non-Human Primates

Blastocystis is a prevalent gut eukaryote intricately associated with the gut microbiota. This genetically diverse protozoan exhibits significant intra-host subtype heterogeneity, yet the implications of this diversity for the host gut microbiome remain poorly understood. Here, we investigated the interactions between Blastocystis and gut microbiota in non-human primates at the level of subtypes, using a comprehensive investigation of gut microbiota for Blastocystis carriers of captive Macaca fascicularis (discovery cohort, n = 100) and Macaca mulatta (validation cohort, n = 26). We identified highly prevalent intra-host co-occurrence patterns of Blastocystis SSU rRNA-based subtypes, primarily dominated by Subtype 1(ST1) or ST3. These patterns were associated with compositional and structural variations in the gut microbiome but were not significantly influenced by host covariates such as sex, age, or BMI. Specifically, Ruminococcaceae-enterotype was enriched in the patterns dominated by ST1, whereas Limosilactobacillus-enterotype was predominantly identified in the patterns dominated by ST3. We discovered that the absolute abundance of Blastocystis was a critical determinant in elucidating this association across concurrent patterns. In vivo experiments in a new cohort (n = 11) demonstrated that lactic acid bacteria, enriched in the Limosilactobacillus-enterotype, were sufficient to reduce Blastocystis load. We validated the strong association between gut microbiome composition and Blastocystis load in M. mulatta, confirming that specific microbial features could quantitatively predict Blastocystis status in both species. Our findings establish a direct link between gut microbial variations, intra-host genetic heterogeneity, and absolute abundance in Blastocystis for non-human primates.

microbiology↗

Modeling dynamic oxygen permeability as a mechanism to mitigate oxygen-induced stresses on photosynthesis and N2 fixation in marine Trichodesmium

Trichodesmium, the predominant marine diazotrophic cyanobacterium, concurrently performs nitrogen (N2) fixation and photosynthesis, the latter of which produces oxygen (O2) that inhibits N2 fixation. Hopanoid lipids in Trichodesmium may play a role in dynamically regulating membrane permeability to O2, potentially alleviating O2 stress on N2 fixation. However, the physiological impacts of this dynamic permeability are not well understood. We developed a model showing that dynamically modulating membrane O2 permeability can enhance N2 fixation and growth of Trichodesmium by over 50%. High O2 permeability (1.5x10-4 of O2 diffusivity in seawater) during strong photosynthesis accelerates O2 exhaust, reducing energy-consuming photorespiration by [~]40%, while low O2 permeability (1.0x10-5 diffusivity) during active N2 fixation minimizes O2 stress on N2 fixation. Together, these mechanisms increase the carbon and iron use efficiencies by [~]70%. Our study provides a mechanistic and quantitative framework for how dynamic O2 permeability benefits Trichodesmium, offering insights potentially applicable to other diazotrophs. IMPORTANCETrichodesmium is a key player in marine N2 fixation, essential for oceanic productivity and global biogeochemical cycles. However, a significant challenge arises from the concurrent photosynthetic production of O2 during N2 fixation, which can inhibit N2 fixation and cause energy-wasting photorespiration. We develop a physiological model showing that Trichodesmium may dynamically regulate membrane O2 permeability to enhance N2 fixation and growth. The model suggests two mechanisms: elevated O2 permeability during the early daytime of strong photosynthesis accelerates O2 exhaust to environment, reducing photorespiration, while reduced O2 permeability later limits O2 influx from environment, lowering wasteful respiration and maintaining a low intracellular O2 level for active N2 fixation. These adaptations improve the efficiency of carbon and iron utilization, thereby facilitating N2 fixation and growth in Trichodesmium. This study sheds light on how Trichodesmium and other N2-fixing microorganisms can optimize their physiological processes in response to environmental challenges. HIGHLIGHTSO_LIWe developed a metabolic flux model of Trichodesmium, which resolves Dynamic cellular Permeability to O2 (DPO2). C_LIO_LIDPO2 increases N2 fixation and growth rates. C_LIO_LIDPO2 increases growth efficiency by reducing carbon wasting processes such as photorespiration and respiratory protection. C_LIO_LIDPO2, as a result, also increases iron utilization efficiency. C_LI

microbiology↗

TaWUS2D regulates the number of grains per spikelet by enhancing the number of fertile ovaries in Multi-Ovary Wheat

Innovative genetic improvements in the staple crop Triticum aestivum (bread wheat) are urgently needed to address the growing global food security crisis. Here, we report the map-based cloning of TaWUS2D, the gene responsible for the dominant multi-ovary phenotype in wheat. Multi-ovary lines are characterized by the development of three fertile ovaries per floret that results in three grains, as opposed to wildtype single ovary wheat. We used HiFi long-reads to assemble a 14.48 Gbp genome scaffold assembly in the background of mutli-ovary wheat line MOV. Using high-resolution genetic mapping, combined with additional genomic resources, we defined the Mov-1 locus to a 135 Kbp region containing two genes. Using five independent deletion mutants and eight TILLING mutants, we demonstrate that a functional WUSCHEL-like protein, TaWUS2D, is required for the multi-ovary phenotype. TaWUS2D is upregulated in the MOV genetic background. This research lays the groundwork for developing new approaches to improve wheat production potential and sustainability in the face of current and future global food challenges.

plant biology↗

TRPV1+ neurons promote cutaneous immunity against Schistosoma mansoni.

Immunity against skin-invasive pathogens requires mechanisms that rapidly detect, repel or immobilize the infectious agent. While bacteria often cause painful cutaneous reactions, host skin invasion by the human parasitic helminth Schistosoma mansoni often goes unnoticed. This study investigated the role of pain-sensing skin afferents that express the ion channel Transient Receptor Potential Vanilloid 1 (TRPV1) in the detection and initiation of skin immunity against S. mansoni. Data show that mice infected with S. mansoni have reduced behavioral responses to painful stimuli and sensory neurons exposed from infected mice have significantly less calcium influx and neuropeptide release in response to the TRPV1 agonist capsaicin. Using both gain- and loss-of-function approaches, data show that TRPV1+ neurons are critical regulators of S. mansoni survival during migration from the skin into the pulmonary tract. Moreover, TRPV1+ neurons were both necessary and sufficient to promote proliferation and cytokine production from dermal {gamma}{delta} T cells as well as neutrophil and monocyte skin accumulation post-infection. These results suggest a model in which S. mansoni may have evolved to inhibit TRPV1+ neuron activation as a countermeasure that limits IL-17-mediated inflammation, facilitating systemic dissemination and chronic parasitism. One sentence summaryThe parasitic helminth Schistosoma mansoni averts IL-17-dependent protective immunity by suppressing skin-innervating TRPV1+ neurons.

immunology↗

Comparative RT-qPCR and qPCR reveals early infection, low-titer infection, and relative cell activity of the HLB bacterium, Candidatus Liberibacter asiaticus

Candidatus Liberibacter asiaticus (Las) is one of the causal agents of citrus huanglongbing (HLB) epidemics worldwide. Due to its fastidious nature, intracellular and systemic infection, detecting Las at early and/or low-titer infection, as well as differentiating between live or dead cells in the host psyllids and citrus plants is critical for effective HLB management. To achieve both sensitive Las detection and differentiation, we employed one-step reverse transcription-quantitative PCR (RT-qPCR) using total nucleic acids as template. This method allows use of both Las 16S rRNA and rDNA as template in the same reaction and increases detection sensitivity by up to 1000-fold in comparison with quantitative PCR (qPCR). The increased sensitivity significantly reduces false negative detection and detects the otherwise undetectable low-titer Las infections. Furthermore, the greater the abundance of 16S rRNA present in the samples, the bigger the Ct gap obtained between RT-qPCR and qPCR results. The numerical Ct gap can be used to deduce relative Las cellular activity and indirectly infer whether cells are alive or dead. In addition, this comparative detection method also can be used to select inoculum and monitor relative cell activity during in vitro Las culture and evaluate the effectiveness of antimicrobial treatments against Las bacteria.

molecular biology↗

Testing the Tests: Using Connectome-Based Predictive Models to Reveal the Systems Standardized Tests and Clinical Symptoms Are Reflecting

BackgroundSubstantial strides have been made in developing connectome-based predictive models that establish connections between external measures of cognition and/or symptoms obtained through testing performed in a clinical setting, and the human functional connectome. Often referred to as brain-behavior modeling such models offer insights into the functional brain organization supporting the test scores of these external measures1-7. Here, we depart from the conventional feed-forward approach and introduce a feed-back approach that provides new insight into the systems the external measures are reflecting and provides a framework for developing new test instruments that better target specific brain systems. MethodsIn fMRI data from 227 demographically and clinically diverse subjects (healthy participants and patients), we a priori define connectivity networks for the six cognitive constructs and employ kernel ridge regression in a predictive modeling framework to quantify each networks contribution to performance across a spectrum of standardized tests. ResultsThis approach provides a ranking of test scores according to the predictive power of each cognitive network, allowing one to choose the best test to probe a specific brain network. It yields a brain-driven process for forming new tests through selection of combinations of measures that probe the same brain systems. These new composite tests yield better external measures, as reflected by higher predictive power in brain-behavior modeling. We also evaluate the inclusion of specific subtests within a composite score, revealing instances where composite scores are reinforced or weakened by subtest inclusion regarding the specificity of the brain network they interrogate. ConclusionsThe brain-behavior modeling problem can be reconfigured to provide a biologically driven approach to the selection of external measures directed at specific brain systems. It opens new avenues of research by providing a framework for the development of measures, both cognitive and clinical, guided by quantitative brain metrics.

neuroscience↗

Test-retest reliability of resting-state EEG intrinsic neural timescales

Intrinsic neural timescales (INTs), which reflect the duration of neural information storage within local brain regions and capacity for information integration, are typically measured using autocorrelation windows (ACWs). Extraction of INTs from resting-state brain activity has been extensively applied in psychiatric disease research. Given the potential of INTs as a neural marker for psychiatric disorders, investigating their reliability is crucial. This study, using an open-source database, aimed to evaluate the test-retest reliability of ACW-0 and ACW-50 under both eyes-open and eyes-closed conditions across three sessions. The intraclass correlation coefficients (ICCs) were employed to quantify the reliability of the INTs. Our results showed that INTs exhibited good reliability (ICC > 0.6) at the whole-brain level across different index types and eye states. Spatially, except for the right temporal region in the eyes-open condition, all other regions showed moderate-to-high ICCs. Over 60% of the electrodes demonstrated moderate-to-high INT ICCs under both eyes-open and eyes-closed conditions, with ACW-0 being more stable than ACW-50. This present study comprehensively assessed the reliability of INT under various conditions, providing robust evidence for their stability in neuroscience and psychiatry.

neuroscience↗

Virally encoded single-chain antibody fragments targeting alpha-synuclein protect against motor impairments and neuropathology in a mouse model of synucleinopathy

Parkinsons disease (PD) is a neurodegenerative disorder mainly characterized by the loss of dopaminergic neurons from the substantia nigra. Affected neurons exhibit intracellular aggregates primarily composed of misfolded and phosphorylated alpha-synuclein (aSyn). In pathological conditions, this presynaptic protein has been shown to be transmitted from cell to cell in a prion-like manner, which contributes to the progression of the disease. Single-chain variable fragments (scFvs) are small polypeptides derived from the binding domains of antibodies that are less immunogenic and have better tissue penetration compared to full antibodies. In this work, we aimed to demonstrate the potential of extracellular scFvs to slow down the propagation of pathological aSyn in an in vivo model of synucleinopathy. We generated scFvs that target aSyn, and tested two of them in a PD mouse model consisting of transgenic M83 mice injected with human aSyn pre-formed fibrils (PFFs). The sequence encoding each anti-aSyn scFv was cloned in a self-complementary AAV2 viral vector, and purified particles were administered intravenously. CNS expression of either scFv protected against the development of paralysis and limb weakness, in addition to significantly reducing pathologic aggregates of phosphorylated aSyn in the brain. Moreover, in vitro results in human iPSCs-derived dopaminergic neurons suggest that the scFvs can mitigate aSyn spreading by preventing its internalization. Overall, our findings demonstrate that single-chain antibody fragments exhibit strong therapeutic potential in a preclinical mouse model. Thus, our minimally invasive, gene-mediated immunotherapy approach has the potential to serve as an effective treatment for halting the progression of Lewy body diseases.

neuroscience↗

Development of a DNA-encoded library screening method DEL Zipper to empower the study of RNA-targeted chemical matter

To date, RNA-targeted chemical matter is under explored due to a lack of robust screening assays. In this study, we present a novel RNA-targeted small molecule screening approach using a specialized DNA-encoded library (DEL). Our findings reveal that the specialized DEL library, called "DEL Zipper", can significantly reduce single-stranded DNA-RNA region interaction signals during various kinds of RNA selection. By performing the selection against both G-quadruplex, we have identified novel hits that interact with RNA targets and the results are validated through binding. This study demonstrates that the "DEL Zipper" method is a robust screening assay that has potential for discovering small molecule ligands for diverse RNA targets.

molecular biology↗

Characterization of Chronotypes Using the Symbolic Aggregate approXimation (SAX) on Actigraphy Data

In this study, we discuss an efficient approach to characterizing chronotypes using Symbolic Aggregate approXimation (SAX) on actigraphy data. Actigraphy, a non-invasive monitoring of human rest/activity cycles, provides valuable insights into sleep-wake behaviors and circadian rhythms. However, the high dimensionality of actigraphy data poses significant challenges in storage, processing, and analysis. To address these challenges, we applied the SAX algorithm to transform continuous time-series actigraphy data into a symbolic representation, enabling dimensionality reduction while preserving essential patterns. We analyzed actigraphy data from the National Health and Nutrition Examination Survey (NHANES) database, covering over 10,000 individuals, and used unsupervised clustering to identify distinct chronotype patterns. The SAX transformation facilitated the application of machine learning techniques, revealing five chronotype clusters characterized by differences in activity onset, resolution, and intensity. Age distribution analysis showed biases towards specific age groups within the clusters, highlighting the relationship between age and chronotype. Key findings include age-related Chronotype variations with younger individuals exhibiting delayed chronotypes with significant differences in sleep onset (SOT) and wake time (WT) compared to older adults, suggesting a phase delay in sleep patterns as age decreases and activity transition dynamics where clusters showed distinct patterns in winding up and winding down periods, providing insights into the dynamics of activity transitions. This study demonstrates the efficiency and effectiveness of SAX in processing large-scale actigraphy data, enabling robust chronotype characterization that can inform personalized healthcare and public health initiatives. Further exploration of SAX integration with other biometric measures could deepen our understanding of human circadian biology and its impact on health and behavior.

systems biology↗